Rheological and Microstructural studies of semi-dense and dense suspensions in a Periodic Poiseuille Flow using Core-Modified Dissipative Particle Dynamics*

Shear-thickening is a nonlinear rheological behaviour often observed in semi-dense and dense suspensions at increasing shear rates and is commonly associated with microstructural changes in the material. Therefore, understanding the rheology-microstructure correlation has a fundamental importance in the development of many industrial and technological processes. Core-Modified Dissipative Particle Dynamics was employed as a computational method to capture the physics involved in the flow of semi-dense and dense suspensions subjected to a periodic Poiseuille flow at two confinement ratios. The interplay between hydrodynamic and frictional interactions in promoting shear- thickening was investigated as well as the microstructure evolution of those systems at increasing shear rates. Velocity profiles were found to increase with the Péclet number and the shear-thickening response was stronger and took place sooner for dense suspensions at narrower gap sizes. The microstructure followed the rheological trend, clusters of particles being bigger in size for denser and more confined systems.